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Actually there's a better way to do this, which is to count tuples

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during the vacuumcleanup scan that we're going to do anyway.  Should
save a few cycles (one calculation per page, not per tuple) as well
as not having to depend on assumptions about heap and index being
in step.
I think this could probably be made to work for GIST too, but that
code looks messy enough that I'm disinclined to try right now.
This commit is contained in:
Tom Lane 2006-02-12 00:18:17 +00:00
parent fd267c1ebc
commit d52a57fc30
1 changed files with 13 additions and 25 deletions
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38
src/backend/access/nbtree/nbtree.c
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@ -12,7 +12,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.139 2006/02/11 23:31:33 tgl Exp $
* $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.140 2006/02/12 00:18:17 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -539,16 +539,12 @@ btbulkdelete(PG_FUNCTION_ARGS)
IndexBulkDeleteCallback callback = (IndexBulkDeleteCallback) PG_GETARG_POINTER(1);
void *callback_state = (void *) PG_GETARG_POINTER(2);
IndexBulkDeleteResult *result;
double tuples_removed;
double num_index_tuples;
double tuples_removed = 0;
OffsetNumber deletable[MaxOffsetNumber];
int ndeletable;
Buffer buf;
BlockNumber num_pages;
tuples_removed = 0;
num_index_tuples = 0;
/*
* The outer loop iterates over index leaf pages, the inner over items on
* a leaf page. We issue just one _bt_delitems() call per page, so as to
@ -566,19 +562,12 @@ btbulkdelete(PG_FUNCTION_ARGS)
* could be stopped on those.
*
* We can skip the scan entirely if there's nothing to delete (indicated
* by callback_state == NULL) and the index isn't partial. For a partial
* index we must scan in order to derive a trustworthy tuple count.
* by callback_state == NULL).
*/
if (callback_state || vac_is_partial_index(rel))
{
if (callback_state)
buf = _bt_get_endpoint(rel, 0, false);
}
else
{
/* skip scan and set flag for btvacuumcleanup */
buf = InvalidBuffer;
num_index_tuples = -1;
}
if (BufferIsValid(buf)) /* check for empty index */
{
@ -634,8 +623,6 @@ btbulkdelete(PG_FUNCTION_ARGS)
deletable[ndeletable++] = offnum;
tuples_removed += 1;
}
else
num_index_tuples += 1;
}
}
@ -663,7 +650,7 @@ btbulkdelete(PG_FUNCTION_ARGS)
result = (IndexBulkDeleteResult *) palloc0(sizeof(IndexBulkDeleteResult));
result->num_pages = num_pages;
result->num_index_tuples = num_index_tuples;
/* btvacuumcleanup will fill in num_index_tuples */
result->tuples_removed = tuples_removed;
PG_RETURN_POINTER(result);
@ -687,6 +674,7 @@ btvacuumcleanup(PG_FUNCTION_ARGS)
BlockNumber *freePages;
int nFreePages,
maxFreePages;
double num_index_tuples = 0;
BlockNumber pages_deleted = 0;
MemoryContext mycontext;
MemoryContext oldcontext;
@ -801,6 +789,12 @@ btvacuumcleanup(PG_FUNCTION_ARGS)
MemoryContextSwitchTo(oldcontext);
continue; /* pagedel released buffer */
}
else if (P_ISLEAF(opaque))
{
/* Count the index entries of live leaf pages */
num_index_tuples += PageGetMaxOffsetNumber(page) + 1 -
P_FIRSTDATAKEY(opaque);
}
_bt_relbuf(rel, buf);
}
@ -847,16 +841,10 @@ btvacuumcleanup(PG_FUNCTION_ARGS)
/* update statistics */
stats->num_pages = num_pages;
stats->num_index_tuples = num_index_tuples;
stats->pages_deleted = pages_deleted;
stats->pages_free = nFreePages;
/* if btbulkdelete skipped the scan, use heap's tuple count */
if (stats->num_index_tuples < 0)
{
Assert(info->num_heap_tuples >= 0);
stats->num_index_tuples = info->num_heap_tuples;
}
PG_RETURN_POINTER(stats);
}